1. Technical Field
This invention relates generally to internal combustion engines, and more particularly to cylinder liners for diesel engines.
2. Related Art
It is known to cool cylinder liners with water in a water-cooling jacket extending about a portion of an outer surface of the cylinder liner. Unfortunately, the outer surface portion of the cylinder liner that comes in contact with the cooling water typically exhibits erosion from cavitation. The cavitation results from localized pressure variations brought on by vibration transmitted throughout the cylinder liner. As a result of these changes in pressure, the formation and disappearance of bubbles (known as cavitation) imparts mechanical forces in the form of shocks to the outer surface of the cylinder liner, which in turn, results in erosion of the cylinder liner outer wall. As expected, the cavitation, and thus, erosion, is typically most severe in regions of greatest vibration, which generally coincides with a region of the cylinder liner wall through which a piston reciprocates.
In an attempt to combat the onset of cavitation erosion, layers of plating have been formed on the outer surface of the cylinder liner, such as chromium, or ceramic layers have been used. However, these attempts are encumbered with increased costs brought on by both relatively expensive materials and inefficient manufacturing processes. Other attempts have incorporated an outer layer of white cast iron, with an underlying layer of martensitic and sorbitic microstructure, followed by the underlying parent material.
A cylinder liner manufactured according to the present invention overcomes or greatly minimizes any limitations of the prior art described above, and provides cylinder liners that can operate in heavy duty applications, while reducing their propensity for cavitation erosion, and thus, improving their useful life, all at a reduced overall cost.